There are different standards in different fields of knowledge. Medical science is different than journalism, which is different from history, which is different from public safety.

In general, a given field has sources that publish information with the highest standard of credibility. In many fields, these are peer-reviewed journals. They may be published by large universities (Harvard Law Review, Oxford Review of Economic Policy), by government bodies (e.g. Smithsonian Magazine, NIHR), by professional organizations (eg. JAMA, Annals of Internal Medicine), or operate independently (e.g. The Lancet, Nature).